Of the latest trends in the consumer electronics industry, none is more vibrant than the sales of home theater systems. Electronics manufacturers are continuously improving audio/video (A/V) receivers which are specialized for the multiple channels required to produce a theater-like surround-sound system. Most receivers being sold on the market are capable of providing Dolby Pro Logic.RTM. surround sound, which is an analog system. Dolby Laboratories has recently developed Dolby Digital.RTM., which is a digital system and superior to the analog system. Consumers with relatively old receivers which do not have surround-sound capabilities need to purchase an additional component to attach to their existing receiver to upgrade to Dolby Pro Logic.RTM.. Similarly, consumers owning an existing receiver with or without Dolby Pro Logic.RTM. capabilities need to purchase an additional component to upgrade to Dolby Digital.RTM.. (Dolby Pro Logic.RTM. and Dolby Digital.RTM. are registered trademarks of Dolby Laboratories.)
A typical home-theater system includes an A/V receiver to which a number of audio and video components may be attached. These components may include a video cassette recorder (VCR), a digital video disc (DVD) player, a television (e.g., a high-definition or a digital television), a compact disc (CD) player, a tape deck, a tuner, a phonograph, an auxiliary amplifier, and an upgrade component to provide surround sound. As for outputs, which are typically connected to loudspeakers, conventional A/V receivers have two main or front channels (right and left) as well as a number of surround-sound channels, including rear right and left channels, a center channel, and a sub-woofer. If a user is listening to the radio through the tuner, then the A/V receiver provides audio output on the front right and left channels. If the user switches to an input with surround-sound capabilities, such as a DVD player, then the A/V receiver provides audio output on the surround-sound channels in addition to the front right and left channels.
One of the difficulties in installing a home-theater system is the compatibility of the existing A/V receiver with the surround-sound components. For example, if a user is listening to an audio signal from a tuner and adjusts the volume (of the front channel speakers) to a comfortable listening level and then switches to a digital surround-sound signal from DVD player, then the level of the audio signal provided to the front channel speakers will be disproportionately higher (or lower) than the level of the digital audio signal provided to the surround-sound speakers. The resulting surround-sound effect will not be balanced or harmonious. To compensate for the disproportionality, a user needs to manually adjust or align the volume control of the A/V receiver with the surround-sound components in order to balance the levels of the multiple surround-sound speakers with the levels of the front channels. This balance of the front speakers with the surround-sound speakers is often an inexact science, in that the user goes by ear, or by what sounds good to him or her, in adjusting the volume level. After adjusting the volume of the A/V receiver, the user then will adjust the volume of the surround-sound environment (including the front right and left channels) through the surround-sound upgrade component, not through the A/V receiver.
These existing systems share a number of drawbacks and disadvantages. For example, each time a user switches from a "regular" two-channel signal (e.g., from a tuner, a tape deck, a phonograph, etc.) to a multiple-channel surround-sound signal, then the volume control of the A/V receiver needs to be adjusted to the predetermined level in order to balance the levels of the front speakers with the levels of the surround-sound speakers. Two remote controls are often needed to perform this volume balancing routine. In addition, the predetermined level of the A/V receiver is set subjectively by an individual user; however, not all of the viewers enjoying an evening of home theater may share the belief that one predetermined level is best.
Accordingly, in view of the foregoing, it is an object of the present invention to provide apparatus and associated methods for mediating and/or obviating the above-mentioned drawbacks of conventional home-theater systems.
It is another object of the present invention to provide apparatus and associated methods for automatically monitoring and adjusting the volume of the surround-sound channels in a home-theater system.
It is yet another object of the present invention to provide a signal regulator which balances the volume level of primary channels and auxiliary channels based on electrical accuracy, rather than on human subjectivity.
It is a further object of the invention to provide a signal regulator for adjusting the level of an auxiliary signal based upon an amplified level of a primary signal.
It is still another object of the present invention to provide a volume-tracking system which only adjusts the volume of auxiliary signals when there is a strong correlation between a signal used as a reference and feedback signal to prevent erroneous volume adjustment.